Graphophone-reproducer.



No. 785,746. PATBNTDD MAD. 28, 1905.

T. H. MACDONALD.

GRAPHOPHONE REPRODUGER.

APPLIDATIDN FILED SDPT.7. 1904.

UNITED STATES Patented March 28, 1905.

PATENT OEEICE.

THOMAS H. MACDONALD, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR TO AMERICAN GRAPHOPHONE COMPANY, OF BRIDGEPORT, CONNECTI- CUT, A CORPORATION OF WEST VIRGINIA.

GRAPHOPHONE-REPRODUCER.

SPECIFICATION forming part of Letters Patent No. 785,746, dated March 28, 1905.

Application filed September '7, 1904:. Serial No. 223,649.

To all whom t may concern:

Be it known that I, THOMAS H. MACDONALD, a citizen of the United States, residing in Bridgeport, Fairfield county, State of Connecticut, have invented a new and useful Improvement in Graphophone Reproducers, which is fully set forth in the following speciiication.

My invention relates to a reproducer of the IO type employing a floating weight, upon which the stylus-lever is pivoted; and the invention consists in so proportioning this floating weight that its center of gravity shall be practically coincident with the fulcrum of the I5 stylus-lever.

In the annexed drawings are illustrated embodiments of my invention.

Figure 1 is a side View, partly broken away, of one embodiment. Fig. 2 is a bottom View 2O of a modified form, and Fig. 3 is a section of another modification.

A represents the main portion or head of a reproducer adapted for engagement in a suitable seat upon the carrier, wIiich is fed along the sound-record in the usual manner. B indicates the diaphragm thereof.

C is the floating weight, pivoted to the head at a and carrying the fulcrum-post D. Upon this post is pivoted the stylus-lever E, be-

tween the inner end of which and the dia-v phragm B is a connection, preferably a link L, that passes through a central aperture c in the weight C, While the outer end of the stylus-lever (preferably in the form of a gooseneck) carries the stylus e. Vhen the floating' weight is an ordinary iiat circular plate, as commonly used heretofore, its center of gravity will of course be at its geometrical center in the middle of the aperture c. Therefore the pressure exerted upon the stylus (which is located beyond the center of gravity) is not equal to the full weight of the floating weight C. According to my present invention I increase the mass of the floating weight at its free end (farthest away from its hinge c) by thickening it, as seen at C', Fig. 1, so that its center of gravity shall be practically coincident with the fulcrum D. Consequently the entire mass or weight of the iioating weight may be conceived of as concentrated into this portion D, where the pressure is applied, and the up-and-down movement of the iioating Weight C is produced through D without any leverage whatever. Therefore every atom of the mass C tends to resist the quick upward blows upon the stylus c caused by the minute normal irregularities of the soundrecord, while the slower movement imparted by abnormal eccentricities of the cylinder F can more readily overcome the inertia of weight C, because there is no leverage to counteract. If the center of gravity should be carried ap preciably beyond the fulcrum D, there would be undue pressure upon the record and more inertia to overcome, which would tend to wear away the record-surface.

Instead of the precise construction of the Heating weight just described I may employ an oval or pear-shaped floating weight M, pivoted at its smaller apex m, as in Fig. 2, or there may be a prolongation N of the floating Weight N, as in Fig. 3, or there may be other modifications, the essential feature being that the floating weight (of whatever design) must be so constructed and proportioned that its center of gravity shall be practically coincident with the fulcrum of its stylus-lever.

Having thus described my invention, I claiml. In a reproducer for graphophones or 8G other talking-machines, a head carrying a diaphragm, a floating weight pivoted to said head, a fulcrum-post located at the center of gravity of said Weight, and a stylus-bar pivoted on said post and connected to said diaphragm.

2. A floating weight for reproducers, having a stylus-lever pivoted thereto at the center of gravity of said weight, substantially as described.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

THOMAS H. MACDONALD.

Witnesses:

C. B. INGALLs, C. A. GIBNER. 

